Simple Inverter install...if there is such a thing.

Cheap Guy

Cheap Guy

Active Member
Aug 29, 2010
111
Michigan
Boat Info
1989 250DA Sundancer
Engines
5.7 Alpha 1
Ok, so my old Norcold TekII fridge burned out, like they usually do, decades ago and I just replaced it with a small dorm refrigerator that has worked great ever since, but it's obviously AC only. The only issue obviously is that if I spend anytime out on the water, I have to keep it closed and use carry on ice chests so anything in it stays cold. Since I've been doing badly needed repairs and upgrades on my boat this year, I really want to come up with a solution. The choices are:

1. Buy a new, $1000 AC/DC fridge.
2. Use an inverter which will power the fridge and other stuff, like a TV, fan, etc., maybe $300 max, all in.

I watched so many of the online tutorials and videos regarding inverter installations for boats but I don't want to go that complicated if it's not necessary. I don't want to connect to my main panel - I have no problem unplugging the fridge from the outlets and plugging it into the inverter when necessary. Is there anything wrong with just connecting to my two batteries, with appropriate wiring and fuses, put the inverter in the storage cabinet next to the fridge and go from there? I have a bunch of HD gift cards I have use so I'd like to use one they sell but I also saw one on HF that has good reviews. I figure 1000w is probably all I'll need.
 
To hardwire it in and be to ABYC code isn't complicated, but it does take some attention to detail and a lot of planning. All the components need to be sized correctly, and correctly installed as 1000W isnt a small inverter. You're not going to find the correct wire and components at HD. You'll also need some specialty tools like a good large gauge crimper.


For ease of use the $1000 fridge is plug and play, and Sea Ray did all the engineering. All you gotta do is screw it in place.
 
I's skip the "and run other things" and just focus on the fridge. 250W +/- should be more than enough, and a whole lot easier to wire up. I used to run a 500W inverter from a cigarette lighter, zero issues.

Marine fridges are silly money....
 
Stee6043 said:
I's skip the "and run other things" and just focus on the fridge. 250W +/- should be more than enough, and a whole lot easier to wire up. I used to run a 500W inverter from a cigarette lighter, zero issues.

Marine fridges are silly money....
Click to expand...
^^^THIS. You probably don't need anywhere near 1000W to run the fridge (even with start surge). Just install the right size wires, the right circuit protection and make sure there's enough cooling airflow in that cabinet and you should be fine. Also remember that it's a pretty big draw on the battery bank so make sure you have enough spare capacity. Even running it on the inverter WHILE you're on the way to the 'hook' destination will make a big difference, as the food and drinks are being kept cold while the batteries are still being charged.
 
Some refrigerator compressors have a difficult time with modified sine wave (cheap) inverters. You will know if your compressor overheats. I don’t think that this is a problem with newer inverter driven refrigerator compressors. Or, you can get a true sine wave inverter.
 
Thanks for all the advice. This refrigerator issue is one of those, "is there a cheaper way?" things that I hoped going the inverter route would be cheaper but after doing all the cost of doing it the RIGHT way, I'm about at the "BOAT = break out another thousand" mark, no matter which route I go. The key is that with just buying a new fridge, it's a simple "plug and play" like someone mentioned. I also found great DC fans and learned if I really needed a TV out on the hook, it would also work with an inexpensive converter. I've done basic automotive electrical before and I don't go too cheap when it come to that stuff cause I have a thing about vehicles burning up - in this case it would be quality wires, fuses and switches, pure sine wave inverter, maybe an extra battery. I was going to put it off for another year but went for a long cruise last night and sure enough, frozen stuff was melting by the time I went back on power and beer didn't have that frosty goodness that I prefer.
 
Cheap Guy said:
....I also found great DC fans and learned if I really needed a TV out on the hook, it would also work with an inexpensive converter. ....
Click to expand...
There are also a LOT of TVs out there that will work directly on DC. Many use 12VDC too, but even if they were different it wouldn't be so hard to rig a DC-to-DC converter to directly convert your 12VDC to whatever the TV needed (maybe 18VDC) rather than putting in an inverter to convert to 120VAC that the tv brick just converts back down to DC.
 
Its easy to spend other peoples money, but I would definitely go for the new AC/DC marine fridge. Here is why:
1. Inverters are inefficient. They consume power to convert 12vdc to 120vac. So you will use more battery power running a 120v fridge via an inverter. Maybe not a big deal for one night, but a few days it might make a difference in how long you can stay out.
2. If I was buying your boat and saw that you had a dorm fridge wired via an inverter, I will have "red flags" and sirens going off about a poorly maintained boat and lots of other issues that had be repaired "on the cheap". I would probably pass on your boat unless I bought it for a really low price so I could find and fix all that kind of stuff. There are others that might not notice or care, but I think your resale will be lower by more than the price difference on a new fridge.

A properly installed inverter is great though, but its pretty costly to install properly. It can't be installed in the bilge, so you need long 12 heavy gauge wiring and fuse and battery switch, and then if you want to wire direct to the 120v panel that is another process that may cost money to do right (safely).

I have an inverter, mounted in a cockpit storage locker, with about 4ft of wiring down into the batteries in the bilge. I did not hardwire the AC side yet. I run a shorepower cable around to the shorepower inlet on the boat. My fridge is an AC/DC model so the 120v inverter power is really only used for the microwave and TV. Mine is a 1800 watt Xantrex.
 
Cheap Guy said:
Thanks for all the advice. This refrigerator issue is one of those, "is there a cheaper way?" things that I hoped going the inverter route would be cheaper but after doing all the cost of doing it the RIGHT way, I'm about at the "BOAT = break out another thousand" mark, no matter which route I go. The key is that with just buying a new fridge, it's a simple "plug and play" like someone mentioned. I also found great DC fans and learned if I really needed a TV out on the hook, it would also work with an inexpensive converter. I've done basic automotive electrical before and I don't go too cheap when it come to that stuff cause I have a thing about vehicles burning up - in this case it would be quality wires, fuses and switches, pure sine wave inverter, maybe an extra battery. I was going to put it off for another year but went for a long cruise last night and sure enough, frozen stuff was melting by the time I went back on power and beer didn't have that frosty goodness that I prefer.
Click to expand...

I can't believe nobody pointed this out sooner, but based on your username I think it was pretty much mandatory that you create this thread and explore your options :):)
 
I have a question for anyone that can answer, I have a 1996 sea ray express cruiser, with a 5.7, from what I researched at WOT I should be around 4400 to 4800 rpm, I'm only getting up to 3900rpm, any advice?
 
Upsmike said:
I have a question for anyone that can answer, I have a 1996 sea ray express cruiser, with a 5.7, from what I researched at WOT I should be around 4400 to 4800 rpm, I'm only getting up to 3900rpm, any advice?
Click to expand...
You should start a new thread, or you're going to get very confusing answers because some are responding to the OP's situation.
 
This one plugs in to your AC setup between the shore power plug and the AC breakers and automatically switches to inverter when unplugged from shore power. Just add a DC disconnect switch and a breaker to the 12v supply from the house battery and there you go. Everything AC in the boat works just like it’s plugged into shore power when you’re underway.

https://a.co/d/5ZBQTDf
 
Upsmike said:
I have a question for anyone that can answer, I have a 1996 sea ray express cruiser, with a 5.7, from what I researched at WOT I should be around 4400 to 4800 rpm, I'm only getting up to 3900rpm, any advice?
Click to expand...
Get rid of the Norcold TekII fridge, too much weight on the boat...
 
Stee6043 said:
I can't believe nobody pointed this out sooner, but based on your username I think it was pretty much mandatory that you create this thread and explore your options :):)
Click to expand...

My username has been pointed out before, lol. It’s actually the reverse when it comes to boats where “buy cheap, buy twice.” really is the rule. The name came about because I’m old school and I’d rather try to fix things on my own to save money AND learn something new rather just throwing money bombs when things break. Plus try and get a boat mechanic or anyone period to do anything during the middle of boat season. This boat has taught me upholstery and pex plumbing just in the past few seasons. I thought this was going to be a good way to learn boat electrical systems but sometimes you just have to go with the easier solution and spend the money if your original assumptions are wrong.
 
Hoplite808 said:
This one plugs in to your AC setup between the shore power plug and the AC breakers and automatically switches to inverter when unplugged from shore power. Just add a DC disconnect switch and a breaker to the 12v supply from the house battery and there you go. Everything AC in the boat works just like it’s plugged into shore power when you’re underway.

https://a.co/d/5ZBQTDf
Click to expand...

Link doesn’t work. Sounds interesting.
 
Cheap Guy said:
Link doesn’t work. Sounds interesting.
Click to expand...
The link worked OK for me, but there's a veritable boatload of reasons why I wouldn't wire that permanently into the electrical system in my boat and use it between the shore power plug and the breakers. As a stand-alone inverter it might be fine though.
 
km1125 said:
The link worked OK for me, but there's a veritable boatload of reasons why I wouldn't wire that permanently into the electrical system in my boat and use it between the shore power plug and the breakers. As a stand-alone inverter it might be fine though.
Click to expand...

They are made to be installed this way. The original inverter in my 1996 came wired from the factory in this manner. Not sure what reason you wouldn’t want to mount it in a way that makes push button power without having to run cords to everything.


@Cheap Guy try this link: https://www.promariner.com/en/p/06150/Inverter-1500W-12V-Modified-Sine
 
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